Bimetallic ZIFs derived 3D acetylene black loading La2O3/Co bifunctional ORR/OER catalysts

• Internal electric field formed at heterointerface to affect catalytic performance. • La-ZIFs-derived catalysts ensure high dispersion of CoN x and formation of oxygen vacancies. • The introduction of RE and AB results in restricted growth of catalytic centers to expose more active sites. A new type of acetylene black (AB) loading La 2 O 3 -Co/AB catalyst derived from rare earth (RE) La-doped zeolite imidazole framework-67 (ZIF-67) was prepared by composite synthesis strategy to make up for the defects of the weak activity and conductivity of single transition metal catalysts. The different coordination forms of La and cobalt hinder the growth of La-ZIF-67 crystals and promote the exposure of active sites, and the La 2 O 3 in the pyrolysis product improves the stability of the catalyst. The introduction of AB provided abundant anchor sites to facilitate the heterojunctions formation and the electronic transfer at the interface. Remarkably, La 2 O 3 -Co/AB showed high ORR half-wave potential and low OER overpotential, which is believed to benefit from the rich CoN x local environment, heterostructure with internal electric field and oxygen vacancies.